I'm looking for a solution for configuring wifi in headless mode, the same way as IoT devices : when not known wifi in range, toggle to AP mode with a predefined SSID, run a small web-server to list available network, and provide inputs to enter network Key.

I didn't find anything, so I'm eager to develop something to solve the problem.

So does someone know a premade solution ?
If not, how should I proceed ? Write a script that modifies wicd/wpasupplicant config files ?

many thanks for the link, this sounds really interesting. I will try to install it on my pi :-)
– Martin SchneiderMar 24 '16 at 16:33

I have tested resin-wifi-connect. It requires to download a resin.io image and is not exactly what I was looking for.
– Martin SchneiderMar 28 '16 at 21:54

It can't be used as a standalone tool ? what a shame :/
– TryumMar 29 '16 at 13:02

I could not use it as a standalone tool. I had to enter my wifi credentials on the resin.io website before downloading the image. Yesterday I found this repository on Github: github.com/jasbur/RaspiWiFi It might be an alternative. I haven't tested it yet.
– Martin SchneiderMar 30 '16 at 19:37